On 28/05/21 10:35AM, Tomi Valkeinen wrote:

On 28/05/2021 10:24, Pratyush Yadav wrote:

quoted

On 28/05/21 10:16AM, Tomi Valkeinen wrote:

quoted

On 26/05/2021 18:23, Pratyush Yadav wrote:

quoted

The devnode can be used by media-ctl and other userspace tools to
perform configurations on the subdev. Without it, media-ctl returns
ENOENT when setting format on the sensor subdev.

Signed-off-by: Pratyush Yadav <redacted>
---

(no changes since v1)

   drivers/media/platform/cadence/cdns-csi2rx.c | 1 +
   1 file changed, 1 insertion(+)

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index 1df21f462f3c..49bed63d5faa 100644
--- a/drivers/media/platform/cadence/cdns-csi2rx.c
+++ b/drivers/media/platform/cadence/cdns-csi2rx.c

@@ -613,6 +613,7 @@ static int csi2rx_probe(struct platform_device *pdev)
   	csi2rx->pads[CSI2RX_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
   	for (i = CSI2RX_PAD_SOURCE_STREAM0; i < CSI2RX_PAD_MAX; i++)
   		csi2rx->pads[i].flags = MEDIA_PAD_FL_SOURCE;
+	csi2rx->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
   	ret = media_entity_pads_init(&csi2rx->subdev.entity, CSI2RX_PAD_MAX,
   				     csi2rx->pads);

I don't understand this one. There's nothing to configure in cdns-csi2rx
from userspace, as far as I can see, so why is the dev node needed? And why
would the lack of csi2rx dev node cause sensor subdev config to fail?

Sensor config does not fail. But when I run media-ctl to set the format
on /dev/media0, I get an error message that comes because the devnode
for the bridge does not exist. I was not 100% sure about this patch but
I figured if media-ctl expects it then it should be exposed.

I don't mind dropping this patch. Just want to make sure what the right
thing to do here is. Should every element of the pipeline have a devnode
or not?

Tbh, I don't know. But I don't see why they should have. Also, my test works
fine if I remove the devnode here.

What media-ctl parameters did you use which fails?

Media controller topology:

  root@j7-evm:~# media-ctl -p
  Media controller API version 5.13.0
  
  Media device information
  ------------------------
  driver         j721e-csi2rx
  model          TI-CSI2RX
  serial
  bus info       platform:4500000.ticsi2rx
  hw revision    0x1
  driver version 5.13.0
  
  Device topology
  - entity 1: cdns_csi2rx.4504000.csi-bridge (5 pads, 2 links)
             type V4L2 subdev subtype Unknown flags 0
             device node name /dev/v4l-subdev0
         pad0: Sink
                 <- "ov5640 9-003c":0 [ENABLED,IMMUTABLE]
         pad1: Source
                 -> "j721e-csi2rx":0 [ENABLED,IMMUTABLE]
         pad2: Source
         pad3: Source
         pad4: Source
  
  - entity 7: ov5640 9-003c (1 pad, 1 link)
             type V4L2 subdev subtype Sensor flags 0
             device node name /dev/v4l-subdev1
         pad0: Source
                 [fmt:UYVY8_2X8/640x480@1/30 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:full-range]
                 -> "cdns_csi2rx.4504000.csi-bridge":0 [ENABLED,IMMUTABLE]
  
  - entity 11: j721e-csi2rx (1 pad, 1 link)
              type Node subtype V4L flags 0
              device node name /dev/video0
         pad0: Sink
                 <- "cdns_csi2rx.4504000.csi-bridge":1 [ENABLED,IMMUTABLE]


Setting resolution on the sensor (with cdns-csi2rx devnode present):

  root@j7-evm:~# media-ctl --set-v4l2 '"ov5640 9-003c":0 [fmt:UYVY8_2X8/1920x1080@1/30]'

The above command works. Setting resolution on the sensor (without the 
devnode present):

  root@j7-evm:~# media-ctl --set-v4l2 '"ov5640 9-003c":0 [fmt:UYVY8_2X8/1920x1080@1/30]'
  Unable to setup formats: No such file or directory (2)

This sets the format correctly on the sensor but fails when it tried to 
set it on the bridge.

-- 
Regards,
Pratyush Yadav
Texas Instruments Inc.